<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <canvas id="canvas" width="600" height="400"></canvas>
  <script>
     /** @type {HTMLCanvasElement} */
     var canvas=document.querySelector("#canvas")
     
    var ctx=canvas.getContext("2d")
    var color=ctx.createRadialGradient(100,120,10,120,120,90)
    color.addColorStop(0,"white")
    color.addColorStop(0.5,"yellow")
    // color.addColorStop(1,"pink")
    ctx.fillStyle=color
    // ctx.fillRect(0,0,600,400)
    // ctx.arc(200,200,300,0,Math.PI*2)
    // ctx.fill()
  // var radgrad = ctx.createRadialGradient(45, 45, 10, 52, 50, 30);
  // radgrad.addColorStop(0, "red");
  // radgrad.addColorStop(0.9, "#019F62");
  // radgrad.addColorStop(1, "rgba(1,159,98,0)");
  // ctx.fillStyle = radgrad;
  ctx.arc(120,120,90,0,Math.PI*2)
  // ctx.fillRect(0, 0, 600, 400);
  ctx.fill()
  // canvas.style.background="red"
  </script>
</body>
</html>